This invention generally relates to marking apparatus and methods and more particularly relates to an apparatus and method for marking a contoured surface having complex topology.
It is often desirable to place an image on a three-dimensional object having a complex topology, such as a vase or a human bust statue. Usually this image is applied manually, which is timely and costly. Attempting to quickly apply the image manually to the object typically results in less precision in placement of the image on the object, which is an undesirable result. Therefore, it is desirable to provide a marking device capable of marking such a three-dimensional object having complex topology.
Devices for marking curved surfaces are known. One such device is disclosed in U.S. Pat. No. 5,119,109 titled "Method And Apparatus For Marking The Inside Surface Of Pipe" issued Jun. 2, 1992 in the name of John A. Robertson. This patent discloses a system wherein dot matrix characters are formed upon the inside surface of a pipe or other curved surface by an array of ink spray nozzles disposed within a marker head assembly. The marker head is moved by a carriage in a manner such that character pixels are formed during movement of the marker head along loci parallel with the longitudinal axis of the pipe. An indexing mechanism engages an outer surface of the pipe to index it from one marking locus to the next marking locus. Also, a translational mechanism moves the carriage from an off-line to an on-line position during operation of the device. However, this patent does not disclose measuring distance of the surface of the pipe from the marker head before marking begins. That is, this patent does not appear to disclose sensing distance of the surface from the marker head, which may be required in order to sequentially mark pipes having different diameters. Moreover, use of the Robertson device does not appear to assure uniform placement of ink on a contoured surface having complex topology, such as a vase or a human bust statue.
Therefore, there has been a long-felt need to provide an apparatus and method for suitably marking a contoured surface of complex topology in a manner which automatically determines the contour of the surface and quickly, yet precisely, applies a marking medium uniformly to predetermined portions of the surface.